libsepol: Fix type alias handling in kernel_to_cil

Type alias rules are not written out when converting a binary kernel
policy to CIL. The problem is that type aliases are not in the
type_val_to_struct array and that is what is being used to find the
aliases.

Since type aliases are only in the types hashtable, walk that to
find the type aliases.

Fixes: 70a480b ("libsepol: Add ability to convert binary
       policy to CIL")

Signed-off-by: James Carter <jwcart2@gmail.com>

libsepol/src/kernel_to_cil.c

@@ -1367,33 +1367,55 @@ static int write_type_decl_rules_to_cil(FILE *out, struct policydb *pdb)
 	return rc;
 }
 
+static int map_count_type_aliases(__attribute__((unused)) char *key, void *data, void *args)
+{
+	type_datum_t *datum = data;
+	unsigned *count = args;
+
+	if (datum->primary == 0 && datum->flavor == TYPE_TYPE)
+		(*count)++;
+
+	return SEPOL_OK;
+}
+
+static int map_type_aliases_to_strs(char *key, void *data, void *args)
+{
+	type_datum_t *datum = data;
+	struct strs *strs = args;
+	int rc = 0;
+
+	if (datum->primary == 0 && datum->flavor == TYPE_TYPE)
+		rc = strs_add(strs, key);
+
+	return rc;
+}
+
 static int write_type_alias_rules_to_cil(FILE *out, struct policydb *pdb)
 {
 	type_datum_t *alias;
 	struct strs *strs;
 	char *name;
 	char *type;
-	unsigned i, num;
+	unsigned i, num = 0;
 	int rc = 0;
 
-	rc = strs_init(&strs, pdb->p_types.nprim);
+	rc = hashtab_map(pdb->p_types.table, map_count_type_aliases, &num);
 	if (rc != 0) {
 		goto exit;
 	}
 
-	for (i=0; i < pdb->p_types.nprim; i++) {
-		alias = pdb->type_val_to_struct[i];
-		if (!alias->primary) {
-			rc = strs_add(strs, pdb->p_type_val_to_name[i]);
-			if (rc != 0) {
-				goto exit;
-			}
-		}
+	rc = strs_init(&strs, num);
+	if (rc != 0) {
+		goto exit;
+	}
+
+	rc = hashtab_map(pdb->p_types.table, map_type_aliases_to_strs, strs);
+	if (rc != 0) {
+		goto exit;
 	}
 
 	strs_sort(strs);
 
-	num = strs_num_items(strs);
 	for (i=0; i<num; i++) {
 		name = strs_read_at_index(strs, i);
 		if (!name) {